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Temporal range: Early Devonian - Recent
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Sarcopterygii
Infraclass: Crossopterygii
(unranked): Rhipidistia
Late Devonian vertebrate speciation saw lobe-finned fish like Panderichthys having descendants such as Eusthenopteron which could breathe air in muddy shallows, then Tiktaalik whose limb-like fins could take it onto land, preceding the first tetrapod amphibians such as Acanthostega whose feet had eight digits, and Ichthyostega with developed limbs, negotiating weed-filled swamps. Lobe-finned fish evolved into Coelacanth species which survive to this day.

The Rhipidistia are a clade of lobe-finned fishes which include the Tetrapods and lungfishes. Taxonomists traditionally considered the Rhipidistia a subgroup of Crossopterygii that described a group of fish that lived during the Devonian consisting of the Porolepiformes and Osteolepiformes.[1] However as cladistic understanding of the vertebrates has improved over the last few decades a monophyletic Rhipidistia is now understood to include the whole of Tetrapoda and of the extant lungfishes.




  1. ^ "Encyclopedia Britannica". Retrieved 3 April 2014.